GH: run tests on all OS

.github/workflows/pytest.yml

@@ -1,13 +1,15 @@
-name: Tests on Ubuntu
+name: Tests on CI
 
 on: [pull_request]
 
 jobs:
   cpu:
-    runs-on: ubuntu-latest
+    name: Tests on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
     if: "!contains(github.event.head_commit.message, 'ci skip')"
     strategy:
       matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
         python-version: ["3.11"]
     steps:
       - uses: actions/checkout@v3
@@ -20,17 +22,26 @@ jobs:
       # GITHUB_PATH is a special file that GitHub Actions uses to modify PATH
       # Writing to this file adds the directory to the PATH for subsequent steps
       - name: Install gopls
+        shell: bash
         run: |
           go install golang.org/x/tools/gopls@latest
-          echo "$HOME/go/bin" >> $GITHUB_PATH
-          
+          if [ "$RUNNER_OS" = "Windows" ]; then
+            echo "$HOME/go/bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+          else
+            echo "$HOME/go/bin" >> $GITHUB_PATH
+          fi
+
       - name: Install uv
+        shell: bash
         run: curl -LsSf https://astral.sh/uv/install.sh | sh
       - name: Create virtual environment
+        shell: bash
         run: uv venv
       - name: Install dependencies
+        shell: bash
         run: uv pip install -e ".[dev]"
       - name: Test with pytest
+        shell: bash
         run: uv run poe test
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v1